sweetening vs syrup

sweetening and syrup both are nouns.

Word	Noun	Adjective	Verb	Adverb
sweetening	Yes	No	No	No
syrup	Yes	No	No	No

As nouns, syrup is a hyponym of sweetening; that is, syrup is a word with a more specific, narrower meaning than sweetening:

Other hyponyms of sweetening include aspartame, honey, saccharin, refined sugar, sugar, sirup, cyclamate.

sweetening (noun)	syrup (noun)
the act of adding a sweetener to food	a thick sweet sticky liquid
an improvement that makes something more agreeable
something added to foods to make them taste sweeter